Tool chuck assembly

ABSTRACT

A tool chuck assembly to firmly retain the cylindrical stem of a tool wherein a plurality of ball elements are frictionally pressed against the stem by a wedge shaped sleeve, the sleeve being movable into and out of engagement with the balls by means of a manually actuatable lever.

O Umted States Patent 11 1 3,674,281

Hedrick July 4, 1972 [54] TOOL CHUCK ASSEMBLY [56] References Cited [72]Inventor: John R. Hedrick, La Crescenta, Calif. UNITED STATES PATENTS3,398,965 8/1968 Cox ..279 30 [73] Ass'gnee 23; Eng'neer'ng 2,959,42211/1960 Manos ..279i30 22 d; Jam 21 1971 Primary ExaminerFrancis S.Husar Att0rneyRobert E. Geauque [21] Appl. No.: 108,466

[57] ABSTRACT 52 us. c1 ..279/30, 279 1 B A tool chuck assembly tofirmly retain the cylindrical stem of [51] Intel B23b31/1o a toolwherein a plurality of ball elements are frictionally 58 Field of Search..279/1 B 22 so Pmssed again the Stem by a wedge shaped being movableinto and out of engagement with the balls by means of a manuallyactuatable lever.

8 Claims, 5 Drawing Figures TOOL cnucx ASSEMBLY BACKGROUND OF THEINVENTION The field of this invention relates to tool holders and moreparticularly to a chuck assembly for a power driven tool structure tofirmly retain the tool in cooperation with the power driven toolstructure.

Power driven tool operating structures are in widespread use at thepresent time. Such structures normally take the form of a portable handheld motor assembly which effect rotation of a chuck assembly. Thestructure may include an electric motor or a pneumatically driven motorassembly. The chuck assembly is to cooperate with the cylindrical sternof a tool such as a drill, abrasive wheel, or the like and fixedlyposition such with respect to the chuck assembly. An example of suchtype of drills would be the electric drill which is employed in eitherhome or manufacturing use. Another example of such a drill would be thepneumatically powered drill which is used by dentists for the purpose ofdrilling into a persons teeth to permit insertion of a metallic fillingto eliminate continual tooth decay.

The common form of a chuck assembly to effect retention of the stem of atool include a plurality of jaws which are to be movable into contactwith the stem of the tool to frictionally hold the tool in cooperationwith the chuck assembly. To effect the movement of these chuck jaws canprove to be a time consuming procedure. In certain environments it isdesirable that the replacement of tools be effected easily and quicklyas possible. The medical doctor or the dentist may be involved in anemergency situation where it is not desirable to lose time in thesubstituting of a different tool. The removal of the one tool should beaccomplished in a single quick movement and the insertion of the othertool be also accomplished in a single quick movement. Further, theretaining force established by the chuck assembly should be.sufficiently positive as to absolutely preclude accidental dislodgementof the tool from the chuck assembly or to permit any relative rotationbetween the tool and the chuck assembly.

It would be desirable to design a chuck assembly for a cylindrical stemof a rotatable tool which accomplishes the above noted objectives, andalso is of simple construction thereby requiring low manufacturing costand low maintenance cost.

SUMMARY OF THE INVENTION The chuck assembly of this invention employsthe use of a main driving shaft which includes a central aperture forreceiving a cylindrical stern of a rotatable tool. A plurality of ballelements are associated within transverse apertures of the shaft and arecapable of coming into contact with the stem of the tool. The ballelements extend radially exteriorly of the outer surface of the shaftand are capable of coming into contact with a wedge shaped sleeve. Thesleeve is biased by a spring which normally locates the balls intocontact with the stem. The sleeve is to be movable against the bias ofthe spring by means of a pivotable lever. A pin is secured to the leverstructure eccentric from the pivotal axis of the lever. Upon pivotingmovement of the lever the pin effects translational movement of thewedge shaped sleeve.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of the chuckassembly of this invention showing the pivotable positions of the leverto effect translational movement of the wedge shaped sleeve;

FIG. 2 is a longitudinal cross sectional view through the chuck assemblyof this invention taken along line 2-2 of FIG.

FIG. 3 is a view similar to FIG. 2 but showing the balls not in contactwith the cylindrical stern of the tool;

FIG. 4 is a sectional view through the friction ball retaining assemblyemployed within this invention taken along line 4-4 of FIG. 2; and

FIG. 5 is a cross sectional view through the pivotal lever structureemployed within this invention taken along line 5-5 of FIG. 2.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT Referring particularly tothe drawing there is shown in FIG. 1 the chuck assembly 10 of thisinvention which includes a fixed outer housing 12, a fixed inner housing14, and a rotatable shaft 16. The inner housing 14 is secured to themotor assembly housing 18. An electric or pneumatic motor is to becontained within the motor assembly housing 18, but such is deemed to beconventional and need not be shown here for purposes of the descriptionof this invention. However, it is to be understood that the motorlocated within the motor assembly housing. 18 is to effectrotationalmovement of the shaft 16.

The shaft 16 includes a longitudinal central opening 20 which is adaptedto receive the cylindrical stem 22 of a tool in a snug fitting manner.It is to be understood that at the free end of the stem 22, a tool is tobe formed or secured thereto such as a drill bit, grinding wheel, or thelike. Again, such tools are deemed to be conventional and need not beshown here for purposes of the description of this invention.

The shaft 16 is rotatably supported by a first bearing assembly 24 withrespect to the outer housing 12 within fixed sleeve 26. Sleeve 26 isfixedly located with respect to the housing 12 by means of ring 28. Thefixed sleeve 26 is integrally secured to the inner housing 14. The firstbearing assembly 24 is located directly adjacent the collet 3|] of thechuck assembly 10. i

The second bearing assembly 32 rotatably supports shaft 16 with respectto the inner housing 14 adjacent the motor assembly housing 18. Securedto the shaft 16 and located adjacent the second bearing assembly 32 isan inner sleeve 34. Inner sleeve 34 extends about shaft 16 substantiallythe entire spaced distance between the first bearing assembly 24 and thesecond bearing assembly 32.

Integrally secured to the inner sleeve 34 is a collar 36. Co]- lar 36 islocated nearer the second bearingassembly 32 than the first bearingassembly 24. Nearer the first bearing assembly 24 than the secondbearing assembly 32 are formed a plurality of apertures within the innersleeve 34. The apertures are to be equidistantly located about the innersleeve 34 with each aperture to cooperate with a ball 38. It is to benoted that three in number of such balls 38 are shown, however anyreasonable number could be employed. The size of the apertures withinthe inner sleeve 34 are such as to be slightly smaller in diameter thanthe diameter of the balls 38. Therefore, each of the apertures withinthe inner sleeve 34 prevent lineally outward movement of its respectiveball 38 with respect to the sleeve 34.

Each of the balls 38 are located within an opening 40 formed withinshaft 16. Each of the balls 38 are capable of coming into contact withthe stem 22. A portion of each of the balls extend radially outward pastthe inner sleeve 34 and are capable of coming into contact with wedgeshaped sleeve 42. It is important that the balls 38 be formed of anextremely hard material of construction such as stainless steel and alsohave a high surface finish. This decreases wear and permits theestablishing of a high frictional contact between the balls 38 and thestem 22. Wedge shaped sleeve 42 includes an exterior annular recess 44.The head 46 of arm 48 is adapted to be located within the confines ofthe annular recess 44. A compression spring 50 is to be located betweenthe collar 36 and the raised aft portion 52 of the wedge shaped sleeve42.

Arm 48 includes an aperture which is to cooperate with pin 54. Pin 54 ispivotally mouted with respect to the arm 48. The pin 54 is fixedlysecured to a pivot shaft 56. The location of pin 54 is eccentric to theaxis of the pivot shaft 56. The pin 54 is actually secured to the lowerportion of a plate fixed which is integrally secured to the pivot shaft56. Pivot shaft 56 is rotatably supported within outer housing 12. A cap60 is secured to that portion of the pivot shaft 56 which extendsexteriorly of the outer housing 12. A resilient seal 62 is locatedbetween the plate 58 and the lower edge of cap 60. Cap 60 is secured bybolts 64 to the inner housing 14. The cap 60 is rotatably mounted inrespect to the outer housing 12. A lever 66 is integrally secured to theexterior surface of the cap 60.

The operation of the chuck assembly of this invention is as follows: Itwill be presumed that the stem 22 of the tool is in cooperation with thecentral opening of the shaft 16 as shown in FIG. 1 of the drawing. Theballs 38 are being forced toward the stem 22 by means of wedge shapedsleeve 42. Such forcing action is effected by means of spring 50reacting against the sleeve 42 through collar 36. As a result, the balls38 are frictionally pressed against the stem 22 causing a secureretention of such within the shaft 16.

If it is now desired to effect removal of the tool stem 22, the operatorthen grasps the lever 66 and effects a 90 rotation of such to thephantom position-as shown in FIG. 1. As a result, the pin 54 pivots 90with respect to the pivot axis of the pivot shaft 56. However, it is tobe noted that although the movement of the pin 54 is angular, suchmovement closely approaches a lineal direction. Therefore, since the pinis connected to the arm 48, the arm 48 is moved lineally in the aftdirection toward the motor assembly housing 18. The head 46 of the arm48 comes into contact with the raised portion 52 of the wedge shapedsleeve 42. As the wedge shaped sleeve 42 is also moved in the aftdirection effecting a compression of the spring 50, the pressing forceof the wedge shaped sleeve 42 upon the balls 38 has now been releasedpermitting the ball 38 to move a slight distance radially outward withrespect to the longitudinal opening 20. The frictional retaining forcecaused by balls 38 against the stem 22 has now been released and removalof stem 22 from the opening 20 is now permitted. The operator is thenfree to insert another stem 22 of another tool if desired.

Upon the stem of the other tool being inserted, the operator thenrotates the lever 66 back to the solid position shown in FIG. 1 of thedrawing. The wedge shaped sleeve 42 again comes into contact with theballs 38 resulting in a frictional contact force being establishedbetween the balls 38 and the stem 22.

What is claimed is:

l. A chuck assembly to retain the stem of a rotatable tool comprising:

a rotatably driven shaft connected to said stem;

a ball assembly being capable of frictionally contacting said .stem in afirst position to retain such within said shaft, said ball assemblybeing movable to a second position to permit removal and entry of saidstem within said shaft;

means to effect movement of said ball assembly into frictional contactwith said stem;

actuation means to effect operation of said means; and

both said means being non-rotatable with respect to said shaft.

2. A chuck assembly as defined in claim 1 wherein:

said means includes a wedge-shaped sleeve, said sleeve beingcontinuously biased by a biasing means to maintain the frictionalcontact of said ball assembly with said stem.

3. A chuck assembly as defined in claim 2 wherein:

said biasing means comprises a compression spring.

4. A chuck assembly as defined in claim 2 wherein:

said actuation means includes an arm connected to said wedge-shapedsleeve, said arm being movable to effect movement of said wedge-shapedsleeve against said biasing means; and

a lever assembly being connected to said am, said lever assembly beingmanually operable to effect said arm movement.

5. A chuck assembly as defined in claim 4 wherein:

said wedge-shaped sleeve includes an annular means, a head portion ofsaid arm to cooperate with said recess.

6. A chuck assembly as defined in claim 1 wherein:

said stem being cylindrical in configuration, said stern being locatablewithin a central longitudinal opening within said driven shaft.

7. A chuck assembly as defined in claim 1 wherein:

said ball assembly being located within said driven shaft,

said ball assembl including a plura lity of separate balls. 8. A chuckassemb y as defined in claim 7 wherein:

said balls being formed of an extremely hard material of constructionand having an outer smooth surface finish.

1. A chuck assembly to retain the stem of a rotatable tool comprising: arotatably driven shaft connected to said stem; a ball assembly beingcapable of frictionally contacting said stem in a first position toretain such within said shaft, said ball assembly being movable to asecond position to permit removal and entry of said stem within saidshaft; means to effect movement of said ball assembly into frictionalcontact with said stem; actuation means to effect operation of saidmeans; and both said means being non-rotatable with respect to saidshaft.
 2. A chuck assembly as defined in claim 1 wherein: said meansincludes a wedge-shaped sleeve, said sleeve being continuously biased bya biasing means to maintain the frictional contact of said ball assemblywith said stem.
 3. A chuck assembly as defined in claim 2 wherein: saidbiasing mEans comprises a compression spring.
 4. A chuck assembly asdefined in claim 2 wherein: said actuation means includes an armconnected to said wedge-shaped sleeve, said arm being movable to effectmovement of said wedge-shaped sleeve against said biasing means; and alever assembly being connected to said arm, said lever assembly beingmanually operable to effect said arm movement.
 5. A chuck assembly asdefined in claim 4 wherein: said wedge-shaped sleeve includes an annularmeans, a head portion of said arm to cooperate with said recess.
 6. Achuck assembly as defined in claim 1 wherein: said stem beingcylindrical in configuration, said stem being locatable within a centrallongitudinal opening within said driven shaft.
 7. A chuck assembly asdefined in claim 1 wherein: said ball assembly being located within saiddriven shaft, said ball assembly including a plurality of separateballs.
 8. A chuck assembly as defined in claim 7 wherein: said ballsbeing formed of an extremely hard material of construction and having anouter smooth surface finish.